The Utility of Cystathionine Assessment Using Proton MRS for the Preoperative Differential Diagnosis of Adult-Type Diffuse Gliomas

BACKGROUND AND PURPOSE: H-MRS for differentiating glioma subtypes and assessed whether combined analysis with 2-hydroxyglutarate (2HG) improves diagnostic performance. MATERIALS AND METHODS: H-MRS (TE = 97 ms). Spectra with severe artifacts were excluded; no cases were excluded on the basis of full width at half maximum (FWHM < 12.8 Hz, 0.1 ppm at 3T). Metabolites were quantified using LCModel, with concentrations normalized to the unsuppressed water signal and relaxation-corrected. Group comparisons of cystathionine levels were performed using Kruskal-Wallis and Bonferroni-corrected pair-wise tests. The receiver operating characteristic analysis evaluated diagnostic performance for differentiating oligodendrogliomas from astrocytomas and glioblastomas. Supplementary analyses excluding spectra with cystathionine Cramér-Rao lower bounds (CRLB) ≥ 50% and combined cystathionine-2HG receiver operating characteristic were also performed. RESULTS: = .003), whereas no significant difference was observed between oligodendrogliomas and glioblastomas. Receiver operating characteristic analysis showed moderate diagnostic performance (area under the curve [AUC] = 0.69 for oligodendroglioma vs astrocytoma; AUC = 0.56 for oligodendroglioma vs glioblastoma). After CRLB-based exclusion, sensitivity increased but specificity decreased (AUC = 0.83 for oligodendroglioma vs astrocytoma). Combining cystathionine with 2HG modestly improved AUCs (0.72 and 0.61, respectively). CONCLUSIONS: H-MRS reflects biologically meaningful metabolic differences among adult-type diffuse gliomas, with higher levels characteristic of oligodendrogliomas compared with astrocytomas. However, overlap with glioblastomas limits its role as a stand-alone discriminator. When interpreted alongside 2HG and conventional imaging features, cystathionine may serve as a supportive metabolic marker to enhance preoperative glioma subtype classification.